I was going to say the exact same thing, but Winston beat me to it! Yep - bigger collar on the bass drum heads because of the wooden hoop. The bass drum head won't fit in a triple flanged hoop.

I must say the youngin's working at the local GC seem to think that you can put any ol' 18" head on a Gretsch Catalina jazz kit. Even after I explained to them why bass drum heads have a bigger collar, they argued back that someone has done it and is not having any problems whatsoever. So I countered, well, is he playing it or looking at it? Awareness is the first big step everyone has to take, everybody!

Okay, so the "bass" head won't fit a triple-flanged hoop, but will the "tom" head fit a bass hoop? Or is that not a good idea?

I understand except for that one lil' detail. Thanks guys! :)

It'll fit, but it's not a good idea because it's not big enough. If you start to put tension on it, the wood hoop could simply slip off of the drum head collar in certain spots, warping the hoop and making it difficult to accurately tune the head. Some people get lucky and never experience a problem because most people have little or no tension on the bass drum head anyway, but that certainly degrades the tuning options that would normally be available to you with the proper-sized head in the first place.

It'll fit, but it's not a good idea because it's not big enough. If you start to put tension on it, the wood hoop could simply slip off of the drum head collar in certain spots, warping the hoop and making it difficult to accurately tune the head. Some people get lucky and never experience a problem because most people have little or no tension on the bass drum head anyway, but that certainly degrades the tuning options that would normally be available to you with the proper-sized head in the first place.

Alright, I get it now. :)
Yeah, the "Tom" head probably wouldn't work, because I like my bass drums to be tuned a bit higher than most.
Thanks for the info you guys, all the best!

__________________
Take care of your drums, one day they'll be vintage!